When we get an optical module, we can see some basic parameters of the optical module from the label, such as optical module packaging form, rate, wavelength and transmission distance. In view of the fact that some novice users who have just started to contact the optical module do not know the meaning of the letters on the optical module or the specific meaning of the parameters. The editor will briefly introduce the content of this aspect and how to choose some optical modules.
The core technical parameters of optical modules include: optical module transmission speed, packaging, transmitting optical power, receiving sensitivity, transmission distance, center wavelength, optical port type, operating temperature, maximum power consumption, etc. We will introduce them one by one below.
Optical module transmission rate
Optical module transmission rate refers to the number of bits transmitted per second, in Mb/s or Gb/s. According to different transmission rates, optical modules can be divided into:
100M optical module: usually 155M, 100Base, FE, etc. on the label on the optical module, you can see that these are 100M optical modules.
Gigabit optical module: Commonly used gigabit optical module rate representation methods are 1G, 1, 25G, 1000Base, GE, etc.
10 Gigabit optical module: Commonly used representation methods for the rate of 10 Gigabit optical modules are 10G, 10GBase, XG, etc.
25G optical module: There are 25G and 25GBase to express the rate of 25G optical module.
40G optical module: There are 40G and 40GBase to express the rate of 40G optical module
100G optical module: There are 100G and 100GBase to express the rate of 100G optical module
400G optical module: There are 400G and 400GBase to express the rate of 400G optical module
Packaging of optical modules
The packaging of optical modules is a standard, which can also be simply understood as the shape of optical modules. The most common package for 100M optical modules and Gigabit optical modules is SFP, the package for 10 Gigabit optical modules is SFP+, and the packages for 25G/40G/100/400G are SFP28/QSFP/QSFP28/QSFP-DD.
Transmitting optical power and receiving sensitivity
Transmitting optical power refers to the output optical power of the light source at the transmitting end of the optical module, which can be understood as the intensity of light; receiving sensitivity refers to the minimum received light of the optical module under a certain rate and bit error rate The unit of power, transmit optical power and receive sensitivity is dBm. In general, the higher the rate, the worse the receiving sensitivity, that is, the greater the minimum received optical power, the higher the requirements for the receiving end components of the optical module.
Transmission distance of optical module
The transmission distance of optical module is divided into short distance, medium distance and long distance. Usually the short-distance transmission refers to the transmission distance below 2km, and the medium distance is 10-20km. ≥30km is long-distance transmission.
The central wavelength of the optical module
The wavelength of the optical module refers to the optical band used for optical signal transmission, and its unit is nanometer (nm). Currently commonly used wavelengths are 850nm, 1310nm and 1550nm, 1270~1610nm of CWDM wavelength and 1525~1565nm or 1570~1610nm of DWDM wavelength. Generally short-distance transmission, generally use 850nm wavelength within 500m. The wavelength of 1310nm is commonly used from 500m to 20km. 20-40km can choose 1310nm, 1550nm. ≥40 usually use 1550nm wavelength.
Optical port type
The common interface types of optical modules include double LC interface, single LC interface, SC interface, and MPO interface. The dual LC interface is suitable for dual-fiber optical modules, and the single LC interface and SC interface are often used for single-fiber bidirectional optical modules. MPO is commonly used in 40G, 100G and other dual-fiber optical modules. There is another problem here is how to distinguish the optical module receiving and receiving optical ports, I will explain it here. For dual-fiber optical modules: the optical module will generally mark: Rx/Tx, or the direction arrows (▼/▲), Rx&▼ represents the receiving end, Tx&▲ represents the transmitting end, and the Tx at one end must be connected to the Rx at the other end , otherwise the two ends cannot be connected. If it is a single-mode single-fiber optical module, then it is divided into: A end and B end (must be used in pairs), because it is a fiber that receives and sends.
Operating temperature range
The optical module is greatly affected by temperature when it is working. If the operating temperature of the optical module is too high or too low, it may affect the normal use of the optical module and even affect the life of the optical module. The operating temperature range of the optical module is divided into the following three types: commercial temperature (0-70°C); extended temperature (-20-85°C): If you use an outdoor node in a tropical area, you can consider a module with an extended temperature. Industrial-grade temperature (-40-85°C): Used in environments with large temperature changes such as outdoors, remote mountainous areas, and tunnels, the industrial-grade optical module will be imported into temperature compensation software, which is used to ensure that the optical module has a stable working current Supply, when the temperature changes, the temperature compensation software will take effect.
Maximum power consumption
The maximum power consumption per second when the optical module is working is called the maximum power consumption. In the context of energy saving, emission reduction, and carbon neutral green environmental protection, optical modules, as one of the important communication components, are used in a huge amount, and low-power optical modules can effectively reduce the cost of data centers.
To sum up, we should select a suitable optical module based on the actual usage conditions, such as the usage environment, power consumption, peer optical module parameters, optical module performance, etc. There are also some users who have difficulty in whether to use the original module or the compatible module. In fact, it is not necessary. If the budget is sufficient, you can choose the original module. If cost is considered, there is nothing wrong with choosing a compatible optical module. At present, compatible manufacturers can be very compatible with various brands of optical modules, and the price is much cheaper than the original module, and the quality can be assured.
The above is the whole content of this article, I hope it can be helpful to everyone.